Staplers and stapler heads for surgically fastening and cutting a bodily tissue or/and organ, including: a stapling jaw configured to include a first stapling jaw portion and a second stapling jaw portion separated from each other by a longitudinal channel. A blade having a sharp edge may be shiftable from a horizontal position to a vertical position so as to allow traveling thereof along the longitudinal channel. First stapling jaw portion may include a first row of tissue fasteners of a first staple size or/and type, and second stapling jaw portion may include a second row of tissue fasteners of a second staple size or/and type. Also described are methods for surgically fastening and cutting a bodily tissue or/and organ.